Temporal resolution of CW fNIRS devices

1 min read

This is a guest post by Ning Liu from Stanford University.

Temporal resolution provides information on the distance of time between the acquisitions of two images (data) of the same area. It is the reciprocal of sampling rate (or acquisition rate) of an fNIRS device. For some devices, sampling rate is a fixed number; for some other ones, sampling rate may depend on number of sources or detectors to use. Why is that? It is because they have different instrumental design. For those with unfixed sampling rate, multiple sources time-share an optical detector by means of a multiplexing circuit that turns the sources on and off in sequence, so that only one source within the detector range is on at any given time. The NIRx system, for instance, are using this type of design. For those with fixed sampling rate, they usually use low frequency modulated light source to provide the excitation light, thus one detector can ‘see’ only one source.

For instance, Hitachi ETG4000 system has sampling rate of 10Hz (from http://www.hitachi.com/businesses/healthcare/products-support/opt/etg4000/contents2.html), thus its temporal resolution is 100ms. Some other device, such as NIRScout, has sampling rate from 2.5 – 62.5 Hz (from https://nirx.net/nirscout/), thus its temporal resolution is 16 – 400ms. Why the sampling rate is changing from 2.5 – 62.5 Hz? That’s because users can choose different number of sources and detectors in their configuration. The more number of sources and detectors to use, the smaller the sampling rate. The following table is from a review article (Scholkmann, et al., 2014) on NeuroImaging volume 85 (2104), a special issue of functional near-infrared spectroscopy. It summarizes the specifications of some popular commercially available fNIRS devices, mainly focused on continuous wave devices.

Time resolution of NIRS devices
Time resolution of NIRS devices (click to enlarge, F. Scholkmann et al. / NeuroImage 85 (2014) 6–27)

本文作者为斯坦福大学刘宁。她提供NIRS培训服务。



文献鸟双 11 特惠


写作助手,把中式英语变成专业英文


Want to receive new post notification? 有新文章通知我

第五十七期fNIRS Journal Club视频 王欣悦博士

Youtube: https://youtu.be/vyo-kECC2Ps 优酷:https://v.youku.com/v_show/id_XNjQzNTA0ODIwMA==.html 肢体语言——
Wanling Zhu
20 sec read

第五十七期fNIRS Journal Club通知2024/11/02, 10am 王欣悦博士

肢体语言——例如人际距离、眼神、手势等,如何影响我们的交流,是一个有趣的谜题。它们是优雅而神秘的代码,无本可依、无人知晓,却又无人不懂。来自南京师范大学的王欣悦博士将分享如何通过fNIRS超扫描技术,
Wanling Zhu
16 sec read

第五十六期fNIRS Journal Club视频 李开云副教授

Youtube: https://youtu.be/bKanFfeV5Ao 优酷:https://v.youku.com/v_show/id_XNjQzNDUzMjU4OA==.html 孤独症谱系障
Wanling Zhu
27 sec read

One Reply to “Temporal resolution of CW fNIRS devices”

  1. Hello Ning and Xu,

    Great read, thanks for this!

    Just wanted to let you know that the NIRScout has been extended to 100hz max sampling rate with the newest version of NIRStar 15-2, so the typical range for sampling with that system would then be roughly ~4-100hz, depending on the source illumination multiplexing sequence.

    Keep up the great work!

    Sincerely,

    Thomas Johannsen
    NIRx Medical Technologies

Leave a Reply

Your email address will not be published. Required fields are marked *